The present invention relates to the art of filling pressurized containers. It finds particular application in conjunction with manually injecting activators into aerosol cans which have been previously charged with liquefied propellants and filled with paints, adhesives, resins or coatings and will be described with particular reference thereto. It is to be appreciated, however, that the present invention may also find application in conjunction with injecting other coating systems, including, but not limited to lubricants, fiberglass resins, SMC resins, adhesives, epoxy, urethane adhesives, and any other products which can be catalyzed or activated and dispensed from aerosol cans.
There are two common methods for filling an aerosol container with propellant, namely, the “under the cup” method which lifts the valve mounting cup and the “pressure filling” method.
More and more, the aerosol industry is resorting to “pressure filling” of the container with propellant rather than “under the cup” or out of the valve cup filling. The reasons are to diminish the loss of costly propellants and to minimize emissions of propellant into the atmosphere. In under the cup filling, a filling head actually lifts the valve cup partially out of the aerosol container and the propellant is driven under pressure through the opening between the bead (opening) of the container and the channel or circular skirt of the valve cup. In pressure filling, after product is placed in the aerosol can, the valve is crimped onto a one-inch diameter opening of the can. Then, propellant is charged into the can through the valve.
Pneumatically operated and hand operated machines have been available for some time for injecting paint and other coatings into precharged aerosol cans. For example, as illustrated in U.S. Pat. No. 3,797,534, such devices commonly included a manual lever for lifting an aerosol can to be charged into contact with a relatively small reservoir, e.g., one quart. A pneumatically operated piston drives the paint from a cylinder at the bottom of the reservoir through the aerosol valve into the can. Another example of an aerosol filling machine is the Omni-Fill® Pump owned by Sherwin-Williams.
Another example of an aerosol can filling machine is the Z-1000 Filling Machine of Seymour of Sycamore, Ill. The machine can include a manual lever and a bottle containing activator. The Z-1000 fills tints, pigments, gel coats and base coats into Seymour's pre-charged cans. The Z-100 is a manually operated pump which adds reducers, catalysts, and hardeners to an aerosol can already filled with paint or coating, propellant and solvent. The filling machine adds activator into a bottle, which then pumps the activator into the aerosol can. A problem with this system is that the pump used does not generate enough pressure to easily pump the activator through the valve of the can. The pumping system also can have leaks.
A disadvantage of using filling machines such as those described is the machines are not typically portable and the filling process must occur at the machine location rather than in the field. Another disadvantage is that the filling machines are expensive.
Still another disadvantage of a filling pump is that it is difficult to provide sufficient pressure to inject the activator into the valve of the aerosol can. The present invention provides a new and improved portable aerosol can filling gun which overcomes the above-referenced deficiencies of the prior systems while providing more advantageous overall results.